1. Field of the Invention
The present invention relates to an image display device that displays each image contained in a group of images picked up in a time series inside a subject or a patient's body.
2. Description of the Related Art
In the field of endoscope, capsule endoscopes of swallow-type equipped with an imaging function and radio communication function have been proposed and in-vivo information acquiring systems for acquiring a group of images inside organs by inserting such a capsule endoscope into the organs of a subject have been developed. A capsule endoscope is swallowed through the month of a subject such as a patient to make observations (examinations) inside the organs. Then, the capsule endoscope moves through organs such as stomach and small intestine due to peristaltic movement or the like until the capsule endoscope is naturally discharged from the subject while at the same time successively picking up images inside organs of the subject (hereinafter sometimes referred to as images inside the subject) at intervals, for example, of 0.5 seconds in a time series.
While the capsule endoscope moves through organs of the subject, images inside the organs picked up by the capsule endoscope are successively transmitted by radio communication to an external receiving device. The receiving device has a receiving antenna and storage medium and functions so as to receive images inside organs transmitted from the relevant capsule endoscope and to successively store the received images inside organs. By carrying such a receiving device, the subject can move about freely throughout a period between a time when a capsule endoscope is swallowed and a time when the capsule endoscope is naturally discharged.
After the capsule endoscope is naturally discharged, a user such as a physician and nurse causes an image display device to capture a group of images inside organs stored in the storage medium of the relevant receiving device to successively display the group of images inside organs on a display monitor of the image display device. The user successively observes the group of images inside the subject being displayed by the image display device so as to be able to diagnose the subject (Refer, for example, to Japanese Patent Application Laid-Open No. 2003-19111).
Some of such image display devices display a time bar that shows images inside organs picked up by a capsule endoscope in a time series and time positions of the whole group of images inside organs and, if there is any bleeding site image (hereinafter referred to as a bleeding image) among the images inside organs, a mark indicating the time position of such a bleeding image is attached onto the time bar (Refer, for example, to Japanese Patent Application Laid-Open No. 2004-337596). An image display device described in this Patent Document 2 detects color information of a group of images inside organs and, based on the detected color information, detects bleeding images from among the group of images inside organs. Such an image display device displays a mark indicating the time position of a bleeding image (hereinafter sometimes referred to as a lesion mark) at positions on the time bar corresponding to the bleeding images detected from among the group of images inside organs. By visually confirming such a lesion mark displayed on the time bar, a user such as a physician and nurse can easily conjecture in which organ of a subject bleeding images contained in the group of images inside organs were picked up.
Some other image display devices display bleeding site images extracted from among a group of images inside a subject in a display area and also displays a predetermined mark near the bleeding site images to notify a user such as a physician and nurse that images currently displayed in the display area are bleeding site images.
Meanwhile, the time bar described above is generally formed of a group of picture elements arranged in a line. A picture element inside the group of picture elements forming the time bar represents a continuous image group having a predetermined number of images contained in the group of images inside organs successively displayed by the image display device. If, for example, a time bar is formed of 1,000 picture elements arranged in a line and the time bar of the 1,000 picture elements shows time positions of a whole group of 60,000 images inside organs picked up by a capsule endoscope, one picture element in the time bar of the 1,000 picture elements represents a continuous image group having 60 images contained in the group of 60,000 images inside organs.
A mark attached to such a time bar only indicates a temporal position of an image representing a group of partial images including bleeding images inside a subject. Thus, there has been a problem that, when a slider is moved to the position of a mark attached to the time bar, it is difficult to identify which of a group of partial images displayed in the display area are bleeding images.
If a mark to indicate a bleeding image is additionally displayed near a bleeding image currently displayed in the display area, there has a possibility that observation of images inside a subject displayed in the display area may be disturbed because the mark also comes into view of a user such as a physician and nurse and flickers.
A lesion mark displayed at a time position on the time bar (that is, a position corresponding to one picture element of the time bar), on the other hand, represents one or more bleeding images in a continuous image group having 60 images represented by such a picture element of the time bar. That is, if at least one bleeding image is contained in a continuous image group having 60 images, such a lesion mark is displayed in the same way regardless of the number of bleeding images. Thus, there has been a problem that, although it is possible to understand the time positions of bleeding images contained in a group of images inside organs by such a lesion mark, it is difficult to understand distribution of the numbers of images in the overall time positions of the groups of images inside organs.